The Biostatistics Core of this Center assists the various Projects and Cores in the design and analysis of clinical, pre-clinical and retrospective studies and management of data in these studies; the Core also coordinates data management systems operating in the Projects and Cores. Specifically, the Biostatistics Core reviews experimental protocols to ensure that proposed designs will allow for the efficient estimation of parameters with appropriate power and will include covariates that will be relevant to the study. When experimental results are analyzed, the Core will validate the use of simple statistical procedures by investigators, and will perform more complex statistical procedures when required, devising new statistical methodologies when necessary. The Core will review manuscripts submitted by investigators for the appropriate statistical presentation. The Core will provide complete data management services to the other Projects and Cores, including design and review of data collection instruments, data entry, cleaning and validation and production of reports and summaries. The Core will also coordinate its own data management systems with the systems of Cores and Projects that will provide their own data management. It will ensure that software and hardware are compatible across projects and that records can be linked across data bases. It will provide quality assurance reviews for data systems and instruments, and will periodically assess the progress of data collection and management of ongoing projects.